1. Field of the Invention
The present invention relates to the field of telecommunications and, more particularly, to communication connections over an ISDN line.
2. Background of the Related Art
In the field of telecommunications, the use of Integrated Services Digital Network (ISDN) is well known. In a typical connection, a user (also referenced as a terminal) is coupled to a serving ISDN for transfer of digital data employing an established protocol. For example, CCITT (Consultative Committee for International Telephone and Telegraph) Recommendation Q.931 (also referred to as the Q.931 specification or protocol) describes user-network messaging for basic call control. This and other protocol standards (such as the CCITT X.25 packet switching protocol) define the manner in which calls are handled and information transferred through an ISDN connection.
One widely used application of an ISDN is in connecting a digital computing device and/or digital information network to the Internet. It is generally known that an ISDN connection provides significant advantage over analog modem lines, mostly due to the faster data transfer rate achievable, as well as the additional connection messaging being transferred. It is also well known that the current configuration for ISDN Basic Rate Interface (BRI) utilizes one D-channel and two B-channels (2B+D). In FIG. 1, a typical ISDN connection to the Internet is illustrated.
In FIG. 1, a computer user (denoted as a customer) is shown coupled to the Internet. The customer can be a single user or a network of multiple users. Thus, block 10, designating the customer in FIG. 1, represents one or more than one computer or processing device, which is coupled to the Internet. Since in most instances, the customer does not have the access directly to the Internet, the customer typically subscribes with an Internet Service Provider (ISP) to obtain Internet access. Block 11 denotes the ISP, which has a connection onto the Internet. A variety of configurations are available for the customer to link to its ISP. Individual users may link by modem connections, but for multiple-user connections, ISDN provides for a much more enhanced solution. Accordingly, in FIG. 1, an ISDN connection is shown connecting the customer (block 10) to its ISP (block 11).
Although not shown, it is appreciated that the ISDN connection between the customer and the ISP generally is made through an exchange, which is typically provided by local telephone company. Also, in a typical configuration, a router (or a port) 12 is utilized by the customer to interface the ISDN line to a terminal or terminals. A similar arrangement is usually present at the ISP""s end to allow multiple customers to access the Internet through the ISP.
In a typical customer-ISP connection to the Internet, the ISDN connection allows either the customer or the ISP to initiate the connection. Similar to a telephone call, the calling party initiates actions for contacting and connecting to the other party. For example, the customer would initiate an outbound call to the ISP to send an electronic message (e-mail) to a third party via the Internet. Alternatively, the customer may want access to the Internet to browse the World Wide Web. In these instances, the customer would initiate the call to the ISP using the ISDN, similar to using the telephone to call the ISP.
Likewise, when the ISP needs to contact the customer, the ISP will initiate the call. For example, when e-mail, destined to the customer, is received by the ISP, the ISP initiates a call to the customer for transferring the e-mail message. These aspects of transferring information between the customer and the ISP are well known.
FIG. 1 illustrates the situation when the ISP is calling the customer to initiate the connection. An incoming call from the ISP is received by the customer. The incoming call is typically processed by the router 12 and in which the router notices the incoming call. The router 12 then initiates a connect so that the connection between the customer and the ISP is complete. This action is analogous to a telephone caller calling a party and the receiving party picking up the handset of a telephone, upon hearing the ringing of the telephone, to complete the connection.
Unlike the ordinary telephone set, the sequence of events for an ISDN connection to complete the connection is more complicated. A detail for an ISDN connection is illustrated in FIG. 2. In order to show the signal flow, the central office or exchange, denoted as the telephone company (TelCo), is shown as block 13. It is appreciated that the connection can be made through a variety of communications networks available and that the call may transfer through more than one exchange or network.
In a sequence of signal flows shown in FIG. 2, a Setup signal or message is initiated when the ISP places a call to the customer. The Setup message includes information to the TelCo to establish the call. The Setup message includes information regarding the called party, as well as information for configuring which B-channel is to be selected for the communication. Sometimes a Setup Acknowledge message is issued by the TelCo to resend (duplicate) the original information or ask for further information. When requested, the caller responds with the information. When the TelCo has all of the necessary information, a Call Proceeding message is issued to the caller notifying the caller that the service request is valid and that the call setup is in progress.
The TelCo then sends its Setup message to the called party, which is the customer in the example shown. This Setup message is not the same Setup message from the ISP, but essentially contains similar content to establish the call. Upon receiving the Setup message, the called party (customer) sends a Call Proceeding message to the TelCo to inform that the call request has been received. Then the called party issues an Alerting message to alert the user that there is an incoming call. When the TelCo receives the Alerting message, it then sends its Alerting message to the caller that the called party is being alerted.
When the called party""s terminal accepts the call, a Connect message is issued to the TelCo and the TelCo further issues a Connect message to the caller. Also, upon receiving the Connect message from the called party, the TelCo issues a Connect Acknowledge message back to the called party. Likewise, a Connect Acknowledge message is initiated by the caller when it receives the connect message from the TelCo. At this point, connection is established between the ISP and the customer and the call is now in the call information phase. If the call is initiated by the customer, to the ISP, the message flow above is repeated, but in this instance the customer is the calling party and the ISP is the called party.
Referring to FIG. 3, it illustrates an example disconnection from an established call connection. In this instance, the party desiring to disconnect initiates a Disconnect message. In the example shown, the customer initiates the Disconnect. The TelCo, upon receiving the Disconnect, issues its Disconnect to the other party. A corresponding Release message is then issued in response by the TelCo and the disconnected party upon receiving the Disconnect message. Upon receiving the Release message, the customer sends a Release Complete message to signal the TelCo to release the B-channel assigned to the customer. Finally, a Release Complete is sent to the ISP to notify the disconnect process is completed.
The above sequence of messages and events for establishing an ISDN connection and disconnecting from it are known. See for example, xe2x80x9cISDNxe2x80x9d by Gary C. Kessler; and specifically, Chapter 7, at pp. 123-152, titled xe2x80x9cThe D-channel Layer 3 Protocol;xe2x80x9d McGraw-Hill; 1990, 1993.
Although ISDN allows for an enhanced communication link, the calling scheme is still patterned as a telephone call from a calling party to a called party. That is, a call is made from a party who needs to connect with another party. When a given call is initiated, the sequence of events shown in FIG. 2 occurs until the connection is made (or the caller disconnects). In the particular example described above, the router 12 of FIG. 1 identifies the incoming call and initiates the connection by issuing a Connect signal. This action establishes a connection and at this point a physical connection is noted and appropriate charges, fees, tariffs are incurred. However, there are instances, where it would be beneficial for one party and/or the other not to complete the connection, but instead signal to the other party to place a return call to the original calling party. One such example is the communication link between an ISP and its customer.
The present invention describes a scheme in which such a return call can be completed without completing the original call.
The present invention describes a technique to process a telephone call from a calling party without accepting the call and subsequently initiating a call to the original calling party or a pre-designated party. An incoming telephone signal is received to commence establishing a communication link with the calling party. The incoming telephone signal may include information which identifies the calling party""s identity. The incoming call from the calling party is prohibited from initiating a connection to establish the communication link.
Instead, the attempt to establish the communication link by the calling party is terminated, for example, by an initiation of a disconnect message. The call from the calling party fails to complete the connection. Then, a call is initiated to the original calling party or to a pre-designated party to establish the communication link in response to the calling party""s earlier attempt to establish the communication link.
Utilizing this technique on an ISDN connection in which a customer is connected to an Internet Service Provider, calls initiated by the Internet Service Provider will not be answered by the customer, but the customer will be alerted and, in response, will place a call to the Internet Service Provider.